The three-highest scoring performances in Gay's career have come when Gasol, the Grizzlies' second-leading scorer and leading rebounder, has been out with an injury. Gasol missed his second straight game Saturday night because of back problems.
"It was obvious that we needed to step up," Gay said after playing almost 52 minutes and helping pick up the offensive loss of Gasol, who averages 19.1 points and 8.9 rebounds. "Some guys needed to step up and some guys needed to log more minutes. So we made out pretty well."
Mike Miller scored 27 points for Memphis, and Kyle Lowry had a career-high 21 points and only one turnover for the Grizzlies, who shot 53 percent and hit seven of eight free throws in the final 21.2 seconds to maintain their lead.
It marked the first Grizzlies overtime win of the season after losing the first three that went to an extra period. Memphis' last win in overtime was Feb. 9, 2007 against Minnesota.
The Clippers never led in regulation, but were up by as many as three in the extra period, thanks to Maggette and Cassell. But Lowry's rebound of a miss by Hakim Warrick (17 points) and stick back with 40 seconds left gave Memphis a 118-117 lead it never relinquished.
"They hit a big play with the rebound that Kyle Lowry got," Maggette said. "They made a good play rebounding the ball. It gave them a momentum.
"At one point, I thought we had them, but that changed everything around, and they got some shots."
The two teams were tied at 108 at the end of regulation after a layup by Maggette with 28.6 seconds left. Maggette stole the ball on the Grizzlies' next possession as Miller drove to the basket, and the Clippers set up the final play during a timeout with 2.9 seconds left.
But Cuttino Mobley's inbounds pass was intercepted by Gay, who missed a desperation shot from midcourt to send the game into overtime.
Los Angeles also was short-handed, playing without center Chris Kaman, the league's third-leading rebounder at 13.9, who sat out with a left shin contusion. Besides Gasol, Memphis point guard Mike Conley was on the inactive list with a chest contusion.
Gay picked up the slack for Gasol, hitting 13 of 25 shots from the field, including 4-of-8 outside the arc, sending Los Angeles to its third loss in four games. Gay also grabbed 12 rebounds.
"It wasn't the prettiest of games," Memphis coach Marc Iavaroni said, "but we battled courageously and fought hard. We finally got some stops at the end when it seemed as if Cassell was going to score every time."
The Clippers also shot well, finishing the game at 52 percent, including Cassell's 10-of-19. However, Cassell missed all four of his shots from 3-point range.
The loss of Kaman allowed Memphis to outrebound Los Angeles 43-34.
"Obviously, we got beat up on the boards pretty good," Clippers coach Mike Dunleavy said. "[We didn't have] an inside presence as far as shot-blocking and a low post presence. We missed it, but they missed that without Pau Gasol."
Both teams shot better than 50 percent in the first half, and Memphis used 19 points from Gay to build a 61-59 halftime lead.
Los Angeles shot 56 percent in the half, and Thomas missed only one of his eight first-half attempts. Memphis, meanwhile connected on 54 percent of its shots.
The shooting touch for both teams extended beyond the arc as they were a combined 12-of-19 from 3-point range.
Miller scored 12 points in the third to help Memphis extend its lead to 90-82 entering the fourth.
The game was the nightcap of a doubleheader at the FedExForum. Earlier in the day, No. 1 Memphis defeated Gonzaga 81-73 for its 43rd straight home win, longest streak in the nation. ... The Grizzlies announced before the game that they have reached a tentative agreement to place G Damon Stoudamire on waivers Monday. Stoudamire was on the inactive list for Saturday's game, and hasn't played since Dec . 30. ... Kaman had started all 39 games for the Clippers before sitting out Saturday. Aaron Williams started in his place. ... The Grizzlies win snapped a 4-game Memphis losing streak in the series. Memphis now leads the series 26-23. The Clippers are one of only three teams over whom the Grizzlies lead the series. The other two are the Charlotte Bobcats and the Toronto Raptors. ... Warrick's 17 points accounted for all of the Grizzlies' points off the bench.